The world's weirdest airplanes

Most of these odd innovations didn't pan out

By By AUBREY COHEN

on February 21, 2013 2:15 PM

Photo: U.S. Air Force

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Boeing's troubles with the 787 Dreamliner are a reminder that innovation is risky, particularly in aerospace. For us, it brought to mind the many odd airplane ideas that actually few during World War II, the Cold War and since. Here are some of our favorites, starting with the Vought V-173 "Flying Pancake."

The idea of the V-173 was to allow flight at very slow speeds, with short takeoffs and landings, and high maneuverability. Designer Charles Zimmerman put the propellers at the wingtips to reduce drag created by airflow at the tips of conventional wings. It flew more than 190 times between 1942 and 1947. less

Boeing's troubles with the 787 Dreamliner are a reminder that innovation is risky, particularly in aerospace. For us, it brought to mind the many odd airplane ideas that actually few during World War II, the ... more

Photo: U.S. Navy

Boeing's troubles with the 787 Dreamliner are a reminder that... Photo-4231979.57203 - SFGate

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This Vought V-173 ended up on display in the Futuroscope theme park, in Vienne, France.

This Vought V-173 ended up on display in the Futuroscope theme park, in Vienne, France.

Photo: Remi Jouan/Wikimedia Commons

This Vought V-173 ended up on display in the Futuroscope theme... Photo-4231980.57203 - SFGate

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The Kalinin K-7 came out before World War II, but we can't resist including it. It was an experimental Soviet aircraft that flew seven times in 1933 before crashing. It had a wingspan of 174 feet (33 feet more than a Boeing B-29 Superfortress), was 92 feet long (seven feet less than a B-29) and used seven engines. Two more were ordered but not completed. The program was canceled in 1935. Fictional drawings depicting the aircraft as much more exotic circulate on the web. less

The Kalinin K-7 came out before World War II, but we can't resist including it. It was an experimental Soviet aircraft that flew seven times in 1933 before crashing. It had a wingspan of 174 feet (33 feet more ... more

Photo: Wikimedia Commons

The Kalinin K-7 came out before World War II, but we can't... Photo-4231978.57203 - SFGate

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The Horten 229 was a German prototype flying wing fighter/bomber during World War II. It conducted test flights in 1944 and 1945, but the war in Europe ended before it could become operational. This is the sole surviving airframe, which the Smithsonian National Air and Space Museum is restoring. less

The Horten 229 was a German prototype flying wing fighter/bomber during World War II. It conducted test flights in 1944 and 1945, but the war in Europe ended before it could become operational. This is the sole ... more

Photo: Michael Katzmann/Wikimedia Commons

The Horten 229 was a German prototype flying wing fighter/bomber... Photo-4231981.57203 - SFGate

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The XB-35 was a flying wing propeller-engine bomber that Northrop got a contract to build in 1941.

The XB-35 was a flying wing propeller-engine bomber that Northrop got a contract to build in 1941.

Photo: U.S. Air Force

The XB-35 was a flying wing propeller-engine bomber that Northrop... Photo-4236088.57203 - SFGate

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But engineering problems delayed the XB-35 program until it became clear that jet engines were the future. The XB-35 continued as a test program, with first flight in 1946. Both XB-35s were scrapped in 1949.

But engineering problems delayed the XB-35 program until it became clear that jet engines were the future. The XB-35 continued as a test program, with first flight in 1946. Both XB-35s were scrapped in 1949.

Photo: U.S. Air Force

But engineering problems delayed the XB-35 program until it became... Photo-4236086.57203 - SFGate

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The Hughes H-4 Hercules is better known by its nickname, "The Spruce
Goose." The H-4 was built to meet a government request in 1942 for a new
cargo and troop carrier. To save metal for other wartime uses, it
substituted wood -- mostly laminated birch, not spruce. less

The Hughes H-4 Hercules is better known by its nickname, "The Spruce
Goose." The H-4 was built to meet a government request in 1942 for a new
cargo and troop carrier. To save metal for other wartime uses, ... more

Photo: Popperfoto, Popperfoto/Getty Images

The Hughes H-4 Hercules is better known by its nickname, "The... Photo-4236479.57203 - SFGate

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The H-4 was the largest flying boat ever built, weighing 400,000 pounds,
with a length of 218 feet long (12 feet longer than the stretched
Boeing 787-9 Dreamliner) and wingspan on 320 feet (60 feet more than an
Airbus A380). It was designed to carry 750 fully equipped troops or two
Sherman tanks. By 1947, the U.S. government had spent $22 million on the H-4 and Hughes
had spent $18 million of his own money. In finally flew, for the first
and only time, on Nov. 2, 1947. less

The H-4 was the largest flying boat ever built, weighing 400,000 pounds,
with a length of 218 feet long (12 feet longer than the stretched
Boeing 787-9 Dreamliner) and wingspan on 320 feet (60 feet more ... more

Hughes kept it in flight-ready condition
until his death in 1976s. It's now in the Evergreen Aviation Museum, in
McMinnville, Ore. We could do a whole gallery on unusual cargo airplanes. In fact, we did, so check it out. less

Hughes kept it in flight-ready condition until his death in 1976s. It's now in the Evergreen Aviation Museum, in McMinnville, Ore. We could do a whole gallery on unusual cargo airplanes. In fact, we did, so ... more

Photo: George Rose, Getty Images

Hughes kept it in flight-ready condition
until his death in... Photo-4236478.57203 - SFGate

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The Convair XFY-1 Pogo was a post-World War II attempt at a vertical takeoff and landing aircraft, conceived to be based on non-carrier ships for intercepting hostile aircraft. Struts mounted to the rear of the airplane compressed several feet to dampen impact on landing, like a pogo stick. The pilot's seat rotated for safety and comfort in vertical and horizontal flight. less

The Convair XFY-1 Pogo was a post-World War II attempt at a vertical takeoff and landing aircraft, conceived to be based on non-carrier ships for intercepting hostile aircraft. Struts mounted to the rear of the ... more

Photo: U.S. Navy

The Convair XFY-1 Pogo was a post-World War II attempt at a... Photo-4236090.57203 - SFGate

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The Convair XFY-1 Pogo flew successfully in 1954 and 1955, but it was difficult to handle, and the Navy turned its focus to fixed-wing jets.

The Convair XFY-1 Pogo flew successfully in 1954 and 1955, but it was difficult to handle, and the Navy turned its focus to fixed-wing jets.

The Navy contracted for the vertical takeoff and landing Lockheed XFV-1 in 1951, at the same times as the competing Convair XFY-1 Pogo. But the XVY got the only engine capable of vertical takeoffs and landings, so the XVF was fitted with a conventional engine. It was scrapped in 1955. less

The Navy contracted for the vertical takeoff and landing Lockheed XFV-1 in 1951, at the same times as the competing Convair XFY-1 Pogo. But the XVY got the only engine capable of vertical takeoffs and landings, ... more

Photo: U.S. Navy

The Navy contracted for the vertical takeoff and landing Lockheed... Photo-4236094.57203 - SFGate

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The Republic XF-84H was designed to combine the speed of jets with the long range, low fuel consumption and low landing speed of propeller aircraft. It made 12 test flights in 1955 and 1956. Eleven of those flights ended in emergency landings. Poor performance and high maintenance requirements kept the aircraft from becoming operational. less

The Republic XF-84H was designed to combine the speed of jets with the long range, low fuel consumption and low landing speed of propeller aircraft. It made 12 test flights in 1955 and 1956. Eleven of those ... more

Photo: U.S. Air Force

The Republic XF-84H was designed to combine the speed of jets with... Photo-4231977.57203 - SFGate

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The Northrop X-4 was built to study the flight characteristics of swept wing semi-tailless aircraft at transonic speeds (about Mach .85). The two X-4s built flew 102 times between 1948 and 1953.

The Northrop X-4 was built to study the flight characteristics of swept wing semi-tailless aircraft at transonic speeds (about Mach .85). The two X-4s built flew 102 times between 1948 and 1953.

Photo: U.S. Air Force

The Northrop X-4 was built to study the flight characteristics of... Photo-4231972.57203 - SFGate

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The Douglas X-3 Stiletto was designed to test features of an aircraft suitable for sustained flights at supersonic speeds and high altitudes. It first flew in 1952, but engine development difficulties forced the use of lower powered engines than originally planned, limiting its potential. less

The Douglas X-3 Stiletto was designed to test features of an aircraft suitable for sustained flights at supersonic speeds and high altitudes. It first flew in 1952, but engine development difficulties forced ... more

Photo: U.S. Air Force

The Douglas X-3 Stiletto was designed to test features of an... Photo-4231974.57203 - SFGate

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The Goodyear Inflatoplane was what it sounds like: an inflatable airplane. Designed in the 1950s, the idea was that it could be dropped behind enemy lines to downed pilots, who would inflate it and fly to safety. The project was cancelled in 1973. less

The Goodyear Inflatoplane was what it sounds like: an inflatable airplane. Designed in the 1950s, the idea was that it could be dropped behind enemy lines to downed pilots, who would inflate it and fly to ... more

Photo: U.S. Army

The Goodyear Inflatoplane was what it sounds like: an inflatable... Photo-4236097.57203 - SFGate

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The Ryan X-13 Vertijet was designed to test the idea of vertical takeoff and landing. After an initial conventional flight with temporary tricycle landing gear in 1955, it took off vertically in 1956 and completed a full vertical-takeoff and landing flight in 1957. less

The Ryan X-13 Vertijet was designed to test the idea of vertical takeoff and landing. After an initial conventional flight with temporary tricycle landing gear in 1955, it took off vertically in 1956 and ... more

Photo: U.S. Air Force

The Ryan X-13 Vertijet was designed to test the idea of vertical... Photo-4231973.57203 - SFGate

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The B-70 Valkyrie was initially envisioned as a high-altitude bomber that could cruse at Mach 3. But the move to missiles led the Kennedy Administration to cancel the program while two XB-70 prototypes were under construction. The focus shifted to using the XB-70 as a testbed for supersonic transport research. The first XB-70A made its first flight on Sept. 21, 1964, but was found to have poor directional stability above Mach 2.5. less

The B-70 Valkyrie was initially envisioned as a high-altitude bomber that could cruse at Mach 3. But the move to missiles led the Kennedy Administration to cancel the program while two XB-70 prototypes were ... more

Photo: U.S. Air Force

The B-70 Valkyrie was initially envisioned as a high-altitude... Photo-3024982.57203 - SFGate

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The second, improved XB-70 took flight on July 17, 1965, achieved Mach 3 on Jan. 3, 1966 and made nine Mach 3 flights by June 1966. Then, on June 8, 1966, it collided in midair with NASA's F-104N chase plane and crashed. The F-104N pilot and XB-70 co-pilot died in the mishap. This photo shows the XB-70A on the left, with most of both vertical stabilizers missing, and the F-104 at the forward edge of the fireball. The first XB-70 was modified and continued to fly, but newer technology displayed the aircraft, which made its final flight on Feb. 4, 1969. less

The second, improved XB-70 took flight on July 17, 1965, achieved Mach 3 on Jan. 3, 1966 and made nine Mach 3 flights by June 1966. Then, on June 8, 1966, it collided in midair with NASA's F-104N chase plane ... more

The Convair NC-131H Total In-Flight Simulator was a modified C-131B transport aircraft used to study how an aircraft would fly before building a full-scale prototype. The first nose featured reconfigurable controls and instrument displays, and onboard computers that simulated the handling characteristics of various aircraft. The second, original flight deck carried two safety pilots who monitored the simulations and could take control in case of a problem. It first flew in 1970. less

The Convair NC-131H Total In-Flight Simulator was a modified C-131B transport aircraft used to study how an aircraft would fly before building a full-scale prototype. The first nose featured reconfigurable ... more

Photo: U.S. Air Force

The Convair NC-131H Total In-Flight Simulator was a modified C-131B... Photo-4231976.57203 - SFGate

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The Martin X-24A was used to test the feasibility of reentry of a manned aircraft from space. It made 28 flights, starting in 1970. It was carried aloft and released around 40,000 feet, fired rocket engines to reach 70,000 feet and then glided back to land in a dry lake bed. less

The Martin X-24A was used to test the feasibility of reentry of a manned aircraft from space. It made 28 flights, starting in 1970. It was carried aloft and released around 40,000 feet, fired rocket engines to ... more

Photo: U.S. Air Force

The Martin X-24A was used to test the feasibility of reentry of a... Photo-4231975.57203 - SFGate

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The NASA Ames-Dryden (AD)-1 was a research aircraft designed to investigate the concept of an oblique (pivoting) wing. The wing could be rotated on its center pivot to its most efficient angle for the speed at which the airplane was flying. The wing could swing to angles of up to 60 degrees. The AD-1 notched 79 test flights from 1979 to 1982. less

The NASA Ames-Dryden (AD)-1 was a research aircraft designed to investigate the concept of an oblique (pivoting) wing. The wing could be rotated on its center pivot to its most efficient angle for the speed at ... more

Photo: NASA

The NASA Ames-Dryden (AD)-1 was a research aircraft designed to... Photo-4231984.57203 - SFGate

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According to NASA: "Although the oblique wing is still considered a viable concept for large transports, the unpleasant flying characteristics of the AD-1 at extreme wing-sweep angles may have discouraged aircraft designers from adopting this configuration." This multiple-exposure photograph shows different wing positions. less

According to NASA: "Although the oblique wing is still considered a viable concept for large transports, the unpleasant flying characteristics of the AD-1 at extreme wing-sweep angles may have discouraged ... more

Photo: NASA

According to NASA: "Although the oblique wing is still... Photo-4231985.57203 - SFGate

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The U.S. Air Force, the Defense Advanced Research Projects Agency and Northrop worked together on the Tacit Blue Whale from 1978 to 1985, to test the advances in stealth technology. Specifically, it demonstrated that curved surfaces on an aircraft slash an airplane's radar visibility. less

The U.S. Air Force, the Defense Advanced Research Projects Agency and Northrop worked together on the Tacit Blue Whale from 1978 to 1985, to test the advances in stealth technology. Specifically, it ... more

Photo: U.S. Air Force

The U.S. Air Force, the Defense Advanced Research Projects Agency... Photo-4231968.57203 - SFGate

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The Tacit Blue Whale flew 135 times between 1982 and 1985, and went on display in 1996 at the National Museum of the U.S. Air Force, in Dayton, Ohio.

The Tacit Blue Whale flew 135 times between 1982 and 1985, and went on display in 1996 at the National Museum of the U.S. Air Force, in Dayton, Ohio.

Photo: U.S. Air Force

The Tacit Blue Whale flew 135 times between 1982 and 1985, and went... Photo-4231969.57203 - SFGate

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The Bell-Boeing V-22 Osprey uses tilting rotors to take off and land like a helicopter, and fly line a fixed-wing aircraft. Technical and cost issues dogged the program from the awarding of the contract to a Bell-Boeing team in 1983 through first flight in 1989 and deployment in 2007. less

The Bell-Boeing V-22 Osprey uses tilting rotors to take off and land like a helicopter, and fly line a fixed-wing aircraft. Technical and cost issues dogged the program from the awarding of the contract to a ... more

The X-29A "almost looked like it was flying backward," according NASA, which worked on the project with the Air Force, Defense Advanced Research Projects Agency and Grumman. Its wings swept forward from the back of the fuselage, behind the horizontal stabilizers (which are usually at the tail). "The complex geometries of the wings and canards combined to provide exceptional maneuverability, supersonic performance, and a light structure," according to NASA. Grumman started building the first of two X-29As in 1982. Test flights continued through 1992. less

The X-29A "almost looked like it was flying backward," according NASA, which worked on the project with the Air Force, Defense Advanced Research Projects Agency and Grumman. Its wings swept forward from the ... more

Photo: Courtesy Photo, U.S. Civilian

The X-29A "almost looked like it was flying backward,"... Photo-4236098.57203 - SFGate

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The Virgin Galactic mothership WhiteKnightTwo is designed to carry Virgin's SpaceShipTwo to around 50,000 feet and then release the smaller ship, which would then rocket into space. It is the largest all carbon composite aviation vehicle ever built. less

The Virgin Galactic mothership WhiteKnightTwo is designed to carry Virgin's SpaceShipTwo to around 50,000 feet and then release the smaller ship, which would then rocket into space. It is the largest all carbon ... more

The Virgin Galactic mothership WhiteKnightTwo is designed to carry... Photo-755117.57203 - SFGate